Most consumers have come to expect scented laundry products and to expect that fabrics which have been laundered also have a pleasing fragrance. Perfume additives make laundry compositions more aesthetically pleasing to the consumer, and in some cases the perfume imparts a pleasant fragrance to fabrics treated therewith. However, the amount of perfume carryover from an aqueous laundry bath onto fabrics is often marginal. Industry, therefore, has long searched for an effective perfume delivery system for use in detergent products which provides long-lasting, storage-stable fragrance to the product, as well as releases fragrance during use to mask wet solution odor and delivers fragrance to the laundered fabrics.
It is known that deposition of fragrance on to surfaces to be cleaned can be greatly enhanced by using fragrance particles. These particles also cue cleanliness for a longer time because they slowly release perfume after cleaning (EP-A-469228). Such particles are made either by supporting the fragrance on a porous carrier or by encapsulating the fragrance in a shell. To some extent the storage stability of fragrances is also improved by using fragrance particles (e.g. WO9621719, U.S. Pat. No. 5,858,959 and WO9711152). Further improvements have been reported by coating such particles (e.g., GB2090278, EP-A-0879874). Nevertheless, in practice the use of such particles have never been satisfactory.
There has been a continuing search for methods and compositions which will effectively and efficiently deliver perfume from a laundry bath onto fabric surfaces. As can be seen from the following disclosures, various methods of perfume delivery have been developed involving protection of the perfume through the wash cycle, with release of the perfume onto fabrics. U.S. Pat. No. 4,402,856, Schnoring et al, issued Sep. 6, 1983, teaches a microencapsulation technique which involves the formulation of a shell material which will allow for diffusion of perfume out of the capsule only at certain temperatures. U.S. Pat. No. 4,152,272, Young, issued May 1, 1979, teaches incorporating perfume into waxy particles to protect the perfume through storage in dry compositions and through the laundry process. The perfume assertedly diffuses through the wax on the fabric in the dryer. U.S. Pat. No. 5,066,419, Walley et al, issued Nov. 19, 1991, teaches perfume dispersed with a water-insoluble nonpolymeric carrier material and encapsulated in a protective shell by coating with a water-insoluble friable coating material. U.S. Pat. No. 5,094,761, Trinh et al, issued Mar. 10, 1992, teaches a perfume/cyclodextrin complex protected by clay which provides perfume benefits to at least partially wetted fabrics.
U.S. Pat. No. 4,209,417 describes how a mixture of polyvinyl alcohol and perfume mixtures is cast into a film. This film does not contain perfume particles as such.
However, even with the substantial work done by industry in this area, a need still exists for a simple, more efficient and effective perfume delivery system which can be used in laundry compositions to provide initial and lasting perfume benefits to fabrics which have been treated with the laundry product. The prior art methods usually rely on complicated process steps of multiple layers or coating of the perfume particle to function as a barrier thereby increasing the cost and complexity of the supply chain. Even then storage stability of the perfume particles is often unsatisfactory. The process whereby granulates are extruded in often difficult to control when particles of the appropriate size and solubility are desired. Another problem that may occur in providing perfumed products is the excessive odor intensity associated with the products. The industry is still searching for improvements in the length of storage time of the laundry compositions without loss of perfume characteristics, in the intensity or amount of fragrance released during the wash process and delivered to fabrics, and in the duration of the perfume scent on the treated fabric surfaces. A need therefore exists for a process to protect perfume particles which overcomes one or more of the above mentioned drawbacks.
By the present invention it has now been discovered that perfume loaded in and/or on to carriers can be effectively protected from premature release of perfume by forming a film of water-reactive material containing inclusions of perfume particles and preparing perfume chips from said film. The carrier may be porous and may be selected to be substantive to fabrics to be able to deposit enough perfume on the fabrics to deliver a noticeable odor benefit even after the fabrics are dry.
The present invention solves the long-standing need for a simple, flexible, cost-effective, storage-stable perfume delivery system which provides consumer—noticeable odor benefits during and after the laundering process, and which has reduced product odor during storage of the composition.